Booster device



NOV. 15, 1966 s, FOSTER 3,285,172

BOOSTER DEVICE Filed May 20, 1965 FIG.2

FIG. 3

FIG.

STEPHEN F FOSTER INVTN'IOR.

m 8M1)? M M AGENT United States Patent 3,285,172 BOOSTER DEVICE Stephen F. Foster, Hopatcong, N..I., assignor to Hercules Incorporated, a corporation of Delaware Filed May 20, 1965, Ser. No. 457,262 The portion of the term of the patent subsequent to June 1, 1982, has been disclairned Claims. (Cl. 102-24) This application is a continuation-in-part of my copending application Serial No. 337,089, filed January 10, 1964, now Patent No. 3,186,340.

This invention relates to booster devices and more particularly to a cap-sensitive booster device which is designed to be interconnected with compatible cap-insensitive explosive cartridges having protrusion means and yieldable seals to form a compressed explosive column assembly such as disclosed in my above-identified copending appli cation.

The primary object of the present invention is to provide a booster device for the above-mentioned service which is simple in construction, economical to manufacture, uniformly reliable and capable of being interconnected in the explosive column assembly in a facile manner wit-h retention of the feature of the compressed explosive column assembly.

Other objects will appear hereinafter, the novel features being set forth in the appended claims.

In accordance with the present invention, there is provided a cap-sensitive booster device which is designed to be interconnected with compatible cap-insensitive explosive cartridges having protrusion means and yieldable seals to form a compressed explosive column assembly, said device comprising a thin-wall substantially cylindrical plastic container having a male coupling and end closure on one end thereof and having a female coupling on the other end thereof, said male coupling having at least one peripheral bead interrupted by a plurality of longitudinal interlocking slots extending a substantial length of the male coupling, said female coupling having a plurality of interrupted peripheral grooves compatible with the bead and the interlocking slots of the male coupling, a longitudinal slot for leg wires extending from the end closure along one of the interlocking slots and along the male coupling to adjacent the female coupling, a capsensitive explosive charge disposed within the container from the end closure to adjacent the female coupling, a coaxially positioned cap well extending through the end closure and into the explosive charge, said cap well adapted to fully accommodate an electric blasting cap and said longitudinal slot for leg wires adapted to accommodate the leg wires thereof, locking indentations associated with the male coupling and the female coupling, and the end closure of said male coupling having protrusion means to contact and to force the yieldable seal of a compatible cap-insensitive explosive cartridge intothe explosive adjacent thereto.

For a more complete understanding of the present invention and for further objects and advantages thereof, reference is now made to the accompanying drawing wherein reference symbols refer to like parts wherever they occur.

FIGURE 1 is a side view of a booster device in ac cordance with the present invention;

FIGURE 2 is an end view of the booster device depicted in FIGURE 1; and

FIGURE 3 is a sectional view of the booster device taken along line 3-3 of FIGURE 1.

With reference to the drawings, a thin-wall elongated blown plastic container 1 has an explosive 2 disposed therein throughout about half the length of the container.

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A yieldable seal 3 is provided within the container 1 adjacent the explosive 2. A slightly tapered male coupling 4 with a convex end closure 5 are formed as a unitary structure in the thin wall at one end of the container 1 and the explosive 2 extends in to the bottom of the coupling. The male coupling 4 has a peripheral bead 6 with no pitch near the lower end thereof which is interrupted by four equally spaced longitudinal interlocking slots 7 which extend a substantial length of the male coupling thus dividing the bead 6 into four equal segments; Positioned midway above each segment of the bead 6 are two female locking indentations 8. The upper side of the bead 6 has its surface at a right angle to the longitudinal axis of the container with its lower side at an angle of about sixty degrees. Similarly, the surface opposite the lower side of the bead is at a right angle and the surface opposite the upper side of the bead is at an angle of about sixty degrees. This arrangement forming the bead grooves 11 with the right angle surfaces and absence of pitch on the bead 6 insures durable interconnection of the booster with a compatible cap-insensitive explosive cartridge in contrast to beveled surfaces and pitch where an assemlby of cartridges including the booster would tend to unscrew when subjected to tension loads as imparted by their own weight. A female coupling 9 adapted to receive the male coupling of a compatible capinsensitive explosive cartridge is provided at the other end of the container 1. The female coupling 9 has four sets of two peripheral grooves each represented by 10, which grooves are compatible with the bead grooves 11 and the interlocking slots 7 of the male coupling 4. Positioned midway above each set of grooves 10 are two male locking indentations 12 compatible to engage the booster with the female locking indentations of a compatible cap-insensitive explosive cartridge.

A coaxially positioned cap well 13 having a liner 14 of aluminum, brass, paper or the like extends into the explosive 2. A longitudinal slot 15 for the leg wires of a blasting cap inserted into the cap well 13 extends from the end closure 5 along one of the interlocking slots 7 and along the male coupling 4 to adjacent the female coupling 9. This arrangement accommodates and protects the leg wires of an ER. cap disposed within the cap well 13 during interconnection of the booster with a compatible cartridge.

Referring now to interconnection of the booster with compatible cap-insensitive explosive charges to form an assembly, the male coupling 4 with alignment of the indentations and grooves of a compatible cartridge within the slots 7 is slidably inserted into the female coupling of the cartridge with the convex end closure 5 exerting a positive compressive force on the yieldable seal and adjacent explosive of the cartridge whereby the yieldable seal is depressed. The slidable insertion of the male coupling 4 proceeds until the upper end wall of the slots-7 engages the upper indentations of the compatible cartridge whereby it is stopped. The bead grooves 11 are now in register with the grooves of the cartridge and the cartridge and the booster 1 are rotated relative to each other whereupon the grooves engage each other and the male looking indentations of the cartridge ride up out of the slots 7 and over the male coupling body 4 into locking engagement with the female locking indentations 8 of the booster. Similarly, another cartridge may be connected to the female coupling of the booster. It will be appreciated that the thin plastic wall of the female coupling 9 is sufficiently elastic'to accommodate the tapered rnale coupling of a compatible cartridge at its upper end to give a tight water resistant fit as additionally disclosed in my aforementioned copending application. Moreover, the length of the slotted portion 7 of the male coupling 4 is correlated with the upper indentation 12 of the female coupling 9 to insure that in assembling the booster 1 in a column of compatible cartridges, the convex end closure of the male coupling exerts a positive compressive force on the yieldable seal and adjacent explosive of the female coupling of a compatible cartridge. This improves the propagating relationship and quite advantageously is accomplished in the field at the time the explosive column including the booster is .being readied for use. Moreover, a tight seal is effected as between the booster and adjacent cartridges as the female coupling being slightly elastic in all the devices has its end maintained in tension as it is forced to accommodate the tapered upper portion of the male couplings.

The following example will serve to illustrate a comrnercially sized preferred embodiment of this invention. It is to be understood, however, that the scope of the invention is not limited thereby with respect to the specific structure or to the explosive charges utilized.

A series of thin-wall containers was formed by blowmolding high-density polyethylene having a density of 0.962 and a nominal melt index of 0.5 (I at 190 C.).-

These containers were molded in a split mold designed to yield the structure heretofore described and illustrated as a preferred embodiment of the invention. Approximate dimensions of the containers were 8% overall length; 2 body diameter; male coupling 4% long with convex end; interlocking slotted portion 1% long, 4;" wide and 7 deep; bead A" long with grooves each side o. to c. and deep; female indentations diameter and deep; female coupling 4" long, grooved midportion of female coupling lf c. to c. and 7 deep; male indentations diameter, 7 deep and slightly tapered and rounded. The liner for the cap well had an inside diameter of and length of 2 was formed of aluminum and was inserted coaxially through the end closure into the container. The longitudinal slot for the leg wires was A" wide and A deep at the end closure and was tapered along the length of the male coupling to become flush adjacent the female coupling. The wall thickness of the body of the container, including the female coupling, was approximately 40 mils, and the wall thickness of the male coupling was approximately 55 mils.

Each of these containers was charged with approximately one pound of explosive composition consisting of 49.0% nitroglycerin, 1.5% nitrocotton, 36.0% sodium nitrate, 7.0% pulp, 3.0% coated cob meal, 2.0% starch, 0.5% bagasse and 1.0% chalk. This charge filled each container from its end closure to adjacent the female coupling or about one-half its length. A polyethylene sealing disk approximately 25 mils thick was then placed over the explosive charge and snugly fitted int-o the container to complete the booster. The booster devices thus manufactured were tested and found to detonate with a No. 8 EB. cap after storage in water at 300 p.s.i. for seven days. Furthermore, the boosters thus manufactured were tested and initiated under conventional field conditions in explosive column assemblies and were satisfactory in all respects with additional advantages hereinafter set forth.

With reference to the foregoing, it will be appreciated that the containers of this invention may be formed in various sizes from many of the plastic materials capable of being blow but that the economy of the material will largely dictate its use. Thus, although linear polyethylene is preferred and has been found highly satisfactory, polyolefins generally, and copolymers and alloys thereof and other materials such as ABS terpolymer, plasticized or rigid poly(vinyl chloride), plasticized vinyl chloridevinyl acetate copolymer and the like may be used. Also, it will be appreciated that in addition to the specific explosive used in the example, other cap-sensitive explosives of various types including rigid and nonrigid compositions may be used such as generally, pentolite, Composition B (59.5% cyclonite, 39.5% TNT, 1.0% wax), gelatins, other dynamites, and the like. It will be appreciated that 4 in using cast rigid compositions, close tolerance in filling must be held to permit interconnection of a superjacent cartridge to the booster, since if filled too high, the end closure of the cartridge will contact the rigid explosive of the booster before the locking elements are in full registry. However, a liner for the cap well and a seal to retain the rigid explosive charge are not necessary, and the elimination of these elements is contemplated within the purview of the invention. Since the adaptation or elimination of these elements is well understood in the art, these features are not further elaborated except to state that when seals are utilized, it is highly preferable that they be of the y eldable type such as disclosed in my aforementioned copending application. Also, it will be appreciated that the leg wire slot may be indented to extend across the end closure and intersect the cap well. However, the booster device as presented herein affords an additional marginal advantage by compressing the leg wires between the end closure and the seal of an interconnected cartridge thus snubbing the leg wires and affording additional protection against the possibility of pulling them from the cap under unusual or accidental circumstances.

From the foregoing, it will be evident to those skilled in the art that various modifications can be made or followed, in the light of the foregoing disclosure and discussion, without departing from the spirit or scope of the disclosure or from the scope of the claims.

What I claim and desire to protect by Letters Patent 1. A cap-sensitive booster device which is designed to be interconnected with compatible cap-insensitive explosive cartridges having protrusion means and yieldable seals to form a compressed explosive column assembly, said device comprising:

(a) a thin-wall substantially cylindrical plastic container having a male coupling and end closure on one end thereof and having a female coupling on the other end thereof, said male coupling having at least one peripheral bead interrupted by a plurality of longitudinal interlocking slots extending a substantial 'length of the male coupling, said female coupling having a plurality of interrupted peripheral grooves compatible with the bead and the interlocking slots of the male coupling,

(b) a longitudinal slot for leg wires extending from the end closure along one of the interlocking slots and along the male coupling to adjacent the female coupling, said longitudinal slot being tapered along the length of the male coupling to become flush adjacent the female coupling,

(c) a cap-sensitive explosive charge disposed within the container from the end closure to adjacent the female coupling,

(d) a coaxially positioned cap well extending through the end closure and into the explosive charge, said cap well adapted to fully accommodate an electric blasting cap and said longitudinal slot for leg wires adapted to accommodate the leg wires thereof,

(e) locking indentations associated with the male coupling and the female coupling, and

(f) the end closure of said male coupling having protrusion means to contact and to force the yieldable seal of a compatible cap-insensitive explosive cartridge into the explosive adjacent thereto.

2. The booster device according to claim 1 wherein the cap-sensitive explosive charge has a yieldable seal and the cap well a liner to retain said explosive charge.

3. The booster device according to claim 1 wherein the cap-sensitive explosive charge is a dynamite.

4. The booster device according to claim 1 wherein the end closure of said male coupling is convex.

5. The booster device according to claim 1 wherein the plastic container is high density polyethylene.

(References on following page) References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS 1,125,984 7/1956 France.

Harte]- 102 24 SAMUEL FEINBERG, Primary Examiner. OErien 102-24 5 BENJAMIN A. BORCHELT, Examiner. Gnficith ct R. v, LOTTMANN, v. R. PENDEGRASS, Foster 102-24 Assistant Examiners. 

1. A CAP-SENSITIVE BOOSTER DEVICE WHICH IS DESIGNED TO BE INTERCONNECTED WITH COMPATIBLE CAP-INSENSITIVE EXPLOSIVE CARTRIDGE HAVING PROTRUSION MEANS AND YIELDABLE SEALS TO FORM A COMPRESSED EXPLOSIVE COLUMN ASSEMBLY, SAID DEVICE COMPRISING: (A) A THIN-WALLED SUBSTANTIALLY CYLINDRICAL PLASTIC CONTAINER HAVING A MALE COUPLING AND END CLOSURE ON ONE END THEREOF AND HAVING A FEMALE COUPLING ON THE OTHER END THEREOF, SAID MALE COUPLING HAVING AT LEAST ONE PERIPHERAL BEAD INTERRUPTED BY A PLURALITY OF LONGITUDINAL INTERLOCKING SLOTS EXTENDING A SUBSTANTIAL LENGTH OF THE MALE COUPLING, SAID FEMALE COUPLING HAVING A PLURALITY OF INTERRUPTED PERIPHERAL GROOVES COMPATIBLE WITH THE BEAD AND THE INTERLOCKING SLOTS OF THE MALE COUPLING, (B) A LONGITUDINAL SLOT FOR LEG WIRES EXTENDING FROM THE END CLOSURE ALONG ONE OF THE INTERLOCKING SLOTS AND ALONG THE MALE COUPLING TO ADJACENT THE FEMALE COUPLING, SAID LONGITUDINAL SLOT BEING TAPERED ALONG THE LENGTH OF THE MALE COUPLING TO BECOME FLUSH ADJACENT THE FEMALE COUPLING, (C) A CAP-SENSITIVE EXPLOSIVE CHARGE DISPOSED WITHIN THE CONTAINER FROM THE END CLOSURE TO ADJACENT THE FEMALE COMPRISING, (D) A COAXIALLY POSITIONED CAP WELL EXTENDING THROUGH THE END CLOSURE AND INTO THE EXPLOSIVE CHARGE, SAID CAP WELL ADAPTED TO FULLY ACCOMODATE AN ELECTRIC BLASTING CAP AND SAID LONGITUDINAL SLOT FOR LEG WIRES ADAPTED TO ACCOMODATE THE LEG WIRES THEREOF, 